Photographic apparatus for spreading a fluid between superposed sheets



'Aug. 5, 1958 H. A. BING ET AL 2,845,850

PHOTOGRAPHIC APPARATUS FOR SPREADING A FLUID BETWEEN SUPERPOSED SHEETS Filed Nov. 4, 1955 2 Sheets-Sheet 1 H. A. BING ET AL PHOTOGRAPHIC APPARATUS FOR SPREADING Aug. 5, 1958 A FLUID BETWEEN SUPERPOSED SHEETS 2 Sheets-Sheet 2 Filed Nov. 4, 1955 United States Patent OfiFice 2,845,850: Patented Aug. 5, 1958 PHOTOGRAPHIC APPARATUS FOR SPREADING A FLUID BETWEEN SUPERPOSED SHEETS Herbert A. Bing, Wellesley, and DonaldR. Bishop, Westwood, Mass., assignors to Polaroid Corporation, Cam bridge, Mass, acorporation of Delaware Application November 4, 1955, Serial No. 544,939 7 Claims. (Cl. 95-43) This invention relates to photography and more particularly to apparatus for distributing a processing liquid between two layers of photographic material.

Apparatus for spreading a liquid in a uniform layer of predetermined thickness between two sheets of flexible photographic material, and particularly between an exposed photosensitive sheet and another sheet, is disclosed in U. S. Patent No. 2,483,014, issued September 27, 1949, in the name of Edwin H. Land et a1. Liquid spreading apparatus of this type generally includes two substantially parallel rigid members predeterminedly spaced apart and so constructed and proportioned with respect to one another as to provide a gap or slot through which the sheet material is drawn. This gap or space between said members comprises a pressure-generating throat whereby a hydraulic pressure is generated in a liquid located between layers of sheet material to spread the liquid between the interface surfaces of the layers as they are drawn between the rigid members. The aforementioned patent defines certain relationships existing between the relative thicknesses of the sheet materials width of the pressure-generating throat, the viscosity of the liquid, the rate at which the sheet material is drawn through the throat, the shape of the members defining the throat and the pressure generated within the liquid; and how these relationships are so controlled as to insure the spread of the liquid over a given area in a layer of substantially uniform predetermined thickness regardless of variations in thickness of the sheet material, the viscosity of the liquid and the speed of movement of the sheet material through the throat.

A liquid-spreading device of this type offers the advantages of simple and inexpensive construction together with dependable and consistent operation resulting in the spreading of a liquid in a uniform layer of predetermined thickness, and is particularly adapted for use in association with photographic apparatus such as a camera wherein a photosensitive sheet is exposed and thereafter processed in conjunction with a second sheet by a layer of liquid distributed between the sheets. The spreading device is so mounted on the camera that the exposed photosensitive and other sheets are superposed and drawn through the spreading gap during Withdrawal of the sheets from the camera. The two members comprising the gap exert pressure in opposite directions in a plane and the most uniform results are achieved when the sheet materials are moved through this gap in another plane perpendicular to the first-mentioned plane. However, withdrawal of a sheet material from the camera through the gap or slot is usually performed manually, the operator grasping the camera or spreading device with one hand and the sheet material with the other hand so that there is no absolute control on the direction of tension on the sheets so that they are not certain to be drawn through the gap in the desired plane, but may be withdrawn in a plane at an angle with respect to the desired plane. This deviation from the desired plane during and layer of liquid and movement of the sheets through the gap results in lack of uniformity of the thickness of the layer of liquid spread between the sheets depending on the angle of deviation.

Accordingly, the invention has, as one object, the provision of a simple and inexpensive device including a substantially fixed gap for distributing a liquid in a unifrom layer of predetermined thickness between two layers of sheet material moved through said gap, said device being so movable with respectto the apparatus on which it is mounted as to automatically adjust and maintain a proper and substantially constant position relative to the plane of movement of said sheet material through said gap.

Other objects of the invention are to provide a fixed gap spreading device capable of being pivotally mounted onphotographic apparatus such as a camera in positionto spread a processing liquid between two layers of photographic sheet material during withdrawal of said sheet material from said apparatus; and to provide, as an element of a photographic film unit comprising a photosensitive sheet and a second sheet superposable with the photosensitive-sheet, a fixed gap spreading device capable of being releasably and movably secured to apparatus for photoexposing said photosensitive sheet.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the apparatus possessing'the construction, combination of elements and arrangement of parts which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For. a' fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings wherein:

Figure 1 is a perspective view embodying the present invention;

Fig. 2 is a sectional view of the film unit' of the invention taken substantially midway between the sides of the film unit;

Fig. 3 is a perspective view, partially broken away, of another form offixed gap spreader;

Fig. 4 is a perspective view, partially broken away, of the. fixed gap spreader of the film unit of Fig. 2;

Fig.5 is a view, partially in section, of a typical camera embodying the invention;

Fig. 6 is a fragmentary perspective view, partially broken away, of the fixed gap spreader of Fig. 5; and

Fig. 7 is a perspective view taken along the line 7-7 of Fig. 6.

The spreading of a fluid composition in a uniformly thin layer between a pair of superposed sheets may be employed for effecting a number of various photographic processes and is particularly adapted, for example, to the processing of an exposed photosensitive stratum on one of the sheets to develop a latent image in the photosensitive stratum and/or produce a positive image in the other sheet by diffusion and transfer of reagents from the photosensitive stratum through or into the fluid layer. The present invention is concerned with the provision of a spreading device adapted to be employed, for example, with a film unit comprising a first sheet having a photosensitive surface stratum and a second sheet superposed with the first sheet and having a surface stratum disposed adjacent the photosensitive stratum and adapted to receive a positive photographic image. The spreading device combines the advantages of accurate control of the fiuid spread with a relatively simple and inexpensive construction, since essentially it comprises only two easily formed, rigid pressure members located in parallel relation to'provide agap or slot through which the film unit is moved, and may be provided either as an element of of a fixed gap spreader c the film unit itself, disposable following processing of the film unit, or as a component of the photographic apparatus, such as a camera, for differentially exposing the photosensitive stratum of the film unit.

.The processing liquid may be supplied in a container interposed between the two sheets of the film unit and adapted to be moved through the gap between the pressure members so as to rupture the container and distribute its contents between the sheets. Since the pressure membersare substantially fixed with respect to one another, it is important that the film unit comprising two sheets and a container be of substantially uniform overall thickness in the vicinity of at least the container and the layer of liquid distributed therefrom between the sheets. One form of film unit of this type is disclosed in application Serial No. 429,185, filed May 12, 1954, in the name of Edwin H. Landet al., and comprises two sheets, i. e., a photosensitive sheet and a second sheet, with portions of the two sheets secured together to define a liquid carrying cavity. Alternatively, the processing liquid may be supplied, as disclosed in the copending application of Edwin H. Land, Serial No. 522,605, filed July 18, 1955, in a container adapted to be removed from the film unit prior to movement thereof between the pressure members and to discharge its contents between the sheets during removal from the film unit so that spreading of the liquid between the sheets is accomplished in the absence of the container. In the form of film unit illustrated in the accompanying drawings, uniformity of thickness is achieved by controlling the relative thicknesses of the sheets in the region of the container and in the region of the layer of liquid between the sheets.

A film unit adapted for use in the present invention is illustrated at in Fig. 2 and comprises a pair of sheets 12 and 14 substantially coextensive with one another and disposed in superposed relation with their inner surfaces in contiguous relation and an elongated container 16 carrying a predetermined quantity of a processing liquid. Each of sheets 12 and 14 comprises two sections, sheet 12 comprising sections 18 and 20 and sheet 14 comprising sections 22 and 24. Sections 20 and 24 are formed of a material which is substantially thicker than the material comprising sections 18 and 22 and are joined to the latter sections by scarf joints 26 and 28 formed by chamfering the edges of the sections and cementing them together at their chamfered edges. The chamfered edges of sections 18 and 22 forming scarf joints 26 and 28 are tapered toward their outer surfaces and are secured to the chamfered edges of sections 20 and 24 with the outer surfaces of the sections of each pair of sections flush with one another so as to present a substantially smooth continuous outer surface at each joint adapted to pass freely through a fixed spreading gap without being snagged or caught by the pressure-applying members forming said gap. The container 16 comprises an elongated strip of sheet material, which is at least impervious to the processing liquid, folded upon itself and sealed together at its edges to provide an elongated cavity extending substantially from side to side of sheets 12 and 14 and carrying the processing liquid. The longitudinal edge seal of container 16 is weaker than the end seals so that the container becomes unsealed along its longitudinal edge in response to the application of compressive pressure to the walls of the container. Container 16 is positioned between sections 18 and 22 of, respectively, sheets 12 and 14 adjacent sections 20 and 24 and with its longitudinal sealed edge located adjacent sections 20 and 24 so that the contents of the container are discharged for spreading therebetween. The liquid contents of the container are preferably quite viscous, having a viscosity, for example, of from 100 to 200,000 centiposes at a temperature of 20 C. for not only insuring a substantially complete rupture of the longitudinal seal of container 16, but for aiding in v the formation of a layer of the liquid between the inner surfaces of the two sheets.

The inner surface of section 20 comprises a photosensitive material such as a silver salt and the liquid incorporates a developing agent capable of forming a visible image in a layer of photosensitive material differentially exposed to actinic light. In a preferred form of film unit, the inner surface of section 20 is coated with a silver halide stratum, section 24 of sheet 14 is coated with a silver precipitating stratum and the processing liquid contains, in addition to a silver halide developer, a silver complexing agent for effecting silver transfer as well as silver reduction. When the liquid is spread between sections 20 and 24, exposed silver halide is reduced to silver and unexposed silver halide forms a complex silver salt which diffuses to the silver precipitating stratum where it forms a positive print.

Film unit 10 is preferably provided with sheets 12 and 14 in superposed relation with sections 18 and 22 secured together to form a leader and sections 20 and 24 secured together at their margins by an adhesive or cement which permits their being stripped apart so that the photosensitive material of section 20 may be exposed. To prevent exposure of the photosensitive material, at least sections 20 and 24 are formed of a material opaque to. actinic light or their outer surfaces are provided with a suitable light-opaque coating. This type of film unit is adapted to be withdrawn into the light after spreading of the processing liquid during the processing period and the processing liquid, being viscous, serves to bond seci tions 20 and 24 together in superposed relation. To prevent the admission of light between sections 20 and 24 through the layer of liquid during processing, the liquid may contain a suitable dye or other material which is opaque to actinic light and does not interfere with the processing.

The spreading device of the present invention, shown in its simplest form in Fig. 1, may comprise an elongated rigid plate 30 having formed therein a narrow elongated slot 32 through which a film unit comprising two sheets may be drawn for spreading a processing liquid between the sheets. The surfaces of plate 30, which form the fixed gap or slot 32 and contact the film unit, are substantially parallel and are preferably shaped to form a convergent entrance throat. The sheets comprising the film unit conform to the shape of this throat and are moved therethrough, causing pressure to be built up in a liquid between the sheets and this pressure thus generated within the liquid results in distribution of the liquid between the sheets in a uniform layer of predetermined thickness. The principles set forth in the aforementioned Patent No. 2,483,014 govern the formation and width of the slot, the thicknesses of the materials and the viscosity of the liquid so that variation in the thicknesses of either or both of the sheets comprising a film unit will cause only minor variations, which are within the acceptable limits, in the thickness of the liquid layer. However, it has been found that the proper function of a fixed gap spreader based on these principles is dependent on the withdrawal of the sheet material through the gap substantially in an optimum plane which is parallel with the axis of the slot or, in other words, perpendicular to the plane of plate 30- or the plane in which pressure is exerted by the walls of the slot on the sheets. When the path of movement of the sheets deviates from this optimum plane, the sheets are curved or bent around one of the exit edges of the slot, causing a back pressure to be generated within the liquid which resists passage of the liquid between the sheets through the slot and resulting in either uncontrolled variation in the thickness of the layer of liquid or in spreading of no liquid at all between the sheets.

While somewhat improved spreading characteristics can be achieved by shaping the walls of the slot to form a divergent exit throat for reducing the sharpness of the bending of the sheets when they are moved in a plane other than the aforementioned optimum plane, uniform spreading of the processing liquid is best assured by moving the sheets through the :gap in the aforementioned optimum plane without substantial deviation therefrom.

As heretofore mentioned, the spreading device of the present invention may comprise either an element of an apparatus such as a camera for exposing a photographic film unit or is provided as an element of the film unit adapted to be secured to the camera when the film unit is positioned for exposure within the camera. A camera of the type useful in association with the present invention is illustrated in Fig. 5 with a film unit positioned therein for exposure and comprises a housing 34 for mounting and enclosing the components of the camera, a conventional lens and shutter assemblage 36 mounted on the forward wall of the housing, a rear wall 38 and a side wall 40 located at an angle with respect-to rear wall 38. The film unit comprises a photosensitive sheet 42 and a second sheet 44 and rear wall 38 is so located with respect to the lens ofassemblage 36 as to be capable of positioning photosensitive sheet 42 disposed against said wall substantially at the focal surface of said lens. Guide means may be provided for holding photosensitive sheet 42 against wall 38 and may comprise, for example, an intermediate apertured wall 46 located adjacent rear wall 38 and having a rear guide surface located substantially at the focal surface of said lens. The camera includes an intermediate side wall 48 located adjacent side wall 40 and defining therebetween a chamber for receiving second sheet 44 of a film unit during exposure of photosensitive sheet 42 positioned between walls 38 and 46. To permit the introduction of a film unit into the camera so that it may be positioned for exposure therewithin, there is provided a narrowelongated passage 50 located at the juncture of walls .38 and 40 and communicating with-the passages between said walls and, respectively, intermediate walls 46 and 48. The film unit is provided with photosensitive sheet 42 and second sheet 44 in superposed relation and passage '50 is adapted to receive the film unit with the sheets so disposed. The two sheets may be cemented together around their edges to hold them in superposed relation and a wedge 52 is provided in passage 50 .at the juncture of walls 46 and 48 for separating the two sheets at their leading ends as they are introduced into passage '50 and for. guiding the two sheets into exposure position as shown and described.

The film unit, camera and spreading device are adapted to manual operation so that, following exposure of the film unit in the camera, withdrawal of the film unit from the camera through the spreader .gap is effected manually with the operator grasping the camera in one hand and the film unit in the other hand. For this reason, there can be no assurance that the film unit is being moved in a single plane during withdrawal and that movement is in the aforementioned optimum plane. However, in accordance with the present invention, provisionis made for automatically adjusting the position of the spreading device with respect to the camera on which it is mounted so that the plane-of movement of the film unit always remains substantially the same with respect to the film unit, regardless of variations in the direction in which the film unit is withdrawn from the camera. This automatic adjustment of the position of the spreader device is achieved by. mounting the spreader device on the camerafor pivotal movement about an axis in theaforementioned optimum plane of movement andpcrpendicular to the direction of movement of the film unit through the gap. This axis of pivotal movement may be located anywhere in the optimum plane of movement on the camera side of the plane in which pressure is'exerted on the film unit or in the lastmentioned plane itself at its intersection with the optimum plane. Spreader plate '30, for example, is adapted to pivotal movement by a pair of shafts or tabs 53 secured or formed integrally with the ends of said plate and adapted to bepivotally secured in suitable detents or holding means comprising the camera with which theplate is employed. Anotherxsimple and inexpensive spreading 8 device embodying the present invention and adapted to be provided as a component of a film unit as illustrated in Fig. 3 of the drawings and comprises two substantially identical pressure members 116 formed, for example, of substantially rigid sheet metal and secured together to provide an elongated fixed spreading gap. Each member 11-6 includes an intermediate section 118 having a straight edge forming one side of the spreading gap and an end section 122 which is substantially wider than section 118 and bent at a right angle to form a dependent mounting arm 124. Members 116 are secured together with the end portion of each section 118 in juxtaposition with the enlarged portion of end section 122 of the other member so that sections 118 of the two membersare located substantially in a plane with their straightedges 120 parallel and predeterminedly spaced apart to define the spreading gap. Edges 120 may be rounded to provide a gap with tapered entrance and exit throats and mounting arms 124 are provided with means such as holes 126 or shafts (not shown), having axes located in a plane through the spreading gap and perpendicular to the plane of sections 118, adapted to cooperate with suitable holding means on a camera for pivotally mounting the spreading device thereon.

A more preferred form of liquid-spreading device comprising an element of a film unit and adapted to be pivotally secured to a camera is shown in Figs. 2 .and 4.

This spreading device, designated at 54, comprises two elongated pressure members 56 each having a U-shaped vcrosssection including a rounded base portion 57 and two substantially parallel legs 58 extending therefrom. Pressure members 56 are mounted at their ends between a pair of L-shaped mounting members 59 with base portions 57 located adjacent one. another in parallel relation and spaced a predetermined distance apart to provide a fixed gap through which the sheetscomprising film unit 10 are moved. This particular U-shaped construction of members 5.6 not only provides for ease in fabrication and assemblage of the spreading device, but gives added rigidity to members 56 so as to resist deformation of said members and variation in the width of the gap due to pressure generated in the liquid between the sheets moving through the gap. The rounded base portions 57 provide an accurately formed gap including curved entrance and exit throats having configurations conforming to the aforementioned principles relating to the design of fixed gap spreading devices. Mounting members 59 each include a base section 60 which extends into slots 62 in theends of base portions 57 of, members 56 and between legs 53 of said members where it is secured, for example, by spot welding when members 56 and 59 are of sheet metal. Section 60 defines the ends ofthe spreading gap, the latter preferably being substantially equal in length to the width oft-he sheet material to be moved therethrough. Members 59 include arm sections 64 extending in the same direction from base section 60 and substantially at right angles thereto and are provided with suitable means such as holes 66 located adjacent their ends for pivotally mounting spreading device 54 on a camera. The camera may include, for example, pins (not shown) adapted to be releasably engaged in holes 66 for pivotally mounting the spreading device.

A film unit including spreading device 54 is provided with sections 18 and 22 secured together and extending through the gap between pressure members 56 and with the portionof sheets 12 and 14 in the vicinity of container 16 being located adjacent members 56. To protect this portion of the film unit including the container from physical damage and to prevent exposure of the photosensitive material during withdrawal of the sheets from the camera through the gap between members 56, there is provided a pair of elongated cover elements 68 formed of an opaque and preferably stiff sheet material, such as paper or cardboard, located on opposite sides of sheets 12 and 14in the vicinity of container 16. Each element 68 is secured along one edge to a member 56 and at its ends to sections 64 of members 59 and with its other longitudinal edge located in contact with one of the sheets comprising the film unit. When the film unit is inserted into the camera, the edges of elements 68 extend partially into passage 50 into lighttight engagement with the walls of the passage and thus form a lighttight chamber exterior of the camera housing between the latter and members 56. This lighttight chamber permits the sheets comprising the film unit to be withdrawn from the camera and super posed with a layer of processing liquid therebetween entirely within a light-free environment even though superposition and spreading of the processing liquid occurs outside of the camera housing.

Reference is now made to Figs. through 7 of the drawings wherein there is illustrated a fixed gap spreading device, generally designated at 70, comprising two members 72 and 74 movable with respect to one another as well as the camera housing on which they are mounted. Members 72 and 74 are preferably formed of a rigid material such as sheet metal and each may be fabricated from a single section of the sheet material. Member 72 comprises a generally rectangular wall 76 having two parallel dependent side walls 78 and a dependent end wall 80. The sheet material comprising end wall 80 is bent or folded back upon itself to form a rounded straight edge section 82 comprising one wall or side of a pressureapplying gap through which the sheets comprising a film unit are adapted to be moved. Member 74 is similar to member 72 and comprises a rectangular wall 84, parallel dependent side walls 86 and a dependent endwall 88 bent back upon itself to provide a rounded straight edge section 90 comprising the other wall of the spreader gap. Side walls 86 of member 74 are so constructed that members 72 and 74 can be mounted on the camera with side walls 86 located or extending between side walls 78 of member 72.

Spreading device 70 is illustrated in a closed or operative position with end walls 80 and 88 located in substantially the same plane and with edge sections 82 and 90 in juxtaposition and predeterminedly spaced apart to form a pressure-applying spreader gap having rounded entrance and exit throats. As a means for accurately spacing edge sections 82 and 90 forming the spreader gap, sections of end wall 88 adjacent side walls 86 are turned back upon I themselves a second time to form spacing members 92 adapted to extend beyond edge section 90 behind end wall 80. Portions of end wall 80 adjacent side wall 78 are turned back upon themselves a second time to form engagement members 94 against which spacing members 92 abut when members 72 and 74 are in closed or operative position. Spacing members 92 additionally define the ends of the spreader gap which is preferably equal in length to the width of the sheet materials adapted to be employed in the camera.

So that the photosensitive and second sheets 42 and 44 of a film unit may be introduced into passage 50 and the container of the film unit located between the passage and end walls 80 and 88 of device 70 without causing the processing liquid to be discharged from the container, members 72 and 74 are mounted on the camera for pivotal movement with respect to one another as well as with respect to the camera so that members 72 and 74 may be spaced apart into inoperative position during introduction of the film unit into the camera. Members 72 and 74 are both pivoted about a single axis located in a plane substantially perpendicular to end walls 80 and 88 through i the center of the spreader gap defined by edge sections 82 and 9t and preferably in the plane of passage 50 in the camera housing. For pivotally mounting members 72 and 74, the camera is provided with such means as a pair of studs or pins 96 secured to side walls 40 of housing 34, preferably in alignment with the open end of passage 50, and side walls 78 and 86 of members 72 and 74, respectively, are provided with holes 98 at which they are mounted on pins 96, said holes being located, as mentioned above with their axes in planes perpendicular to end walls and 88 through the center of the spreader gap. This mounting of members 72 and 74 for pivotal movement about a single axis located in alignment with the open end of passage 50 and in a plane properly located with respect to the members insure that the sheets comprising a film unit will be withdrawn from passage 50 through the spreader gap in the aforementioned optimum plane with respect to the spreading device regardless of the direction in which the sheets are drawn relative to the camera.

Latch means are provided for releasably retaining members 72 and 74 in operative position and include side walls 78 and 86, which are so formed as to overlap one another in both operative and inoperative positions, and a pair of latch pins100. Each latch pin 100 comprises a manually engageable button 102, a round shank portion 104 and an enlarged end portion 106, the shank portion of said latch pin being substantially equal in length to the distance between the inside surface of the side wall 86 and the outside surface of the overlapping side wall 78, or slightly longer than the combined thicknesses of the overlapping portions of a side wall 78 and a side wall 86 when said portions are disposed in contact with one another. The overlapping portions of side walls 78 are each provided with a round hole 108 adjacent the edge of said portion and substantially equal in diameter to shank portion 104, latch pin 100 being mounted in said holes for limited axial movement. The overlapping portions of side walls 86 are provided with larger holes 110 located in alignment with holes 108 when members 72 and 74 are operatively positioned, holes 110 being so formed as to receive the enlarged end portions 106 of latch pins 100 to prevent relative movement of members 72 and 74 with respect to one another. To permit the limited pivotal movement of members 72 and 74 into inoperative position, the overlapping portions of side walls 86 include slots 112 which are substantially equal in width with the diameter of shank portions 104 and which open into holes 110. Slots 112 extend from holes 110 toward the edges of walls 86 and the sides of slots 112 are curved about the pivotal axis of the spreader device, that is, about the axis of holes 98. Resilient means, such as springs 114 secured to side walls 86 and bearing against the ends of latch pins 100, are provided for urging the pins outward and thereby holding enlarged end portions 106 in engagement in holes 110. The members are released from operative position by pressure on buttons 102 for depressing pins 100 against the bias of springs 114 to disengage enlarged end portions 106 from holes 110 so that shank portions 104 slide freely in slots 112. Spring means may be provided for urging members 72 and 74 apart from one another into inoperative position when buttons 102 are depressed.

By virtue of the close fit between side walls 78 and 86,

' members 72 and 74 form a substantially lighttight chamber exterior of passage 50 between said passage and the spreader gap in which the sheets comprising a film unit may be withdrawn from the camera and superposed without danger of exposing the photosensitive material. Suitable light-shielding means or bafiles may be provided on members 72 and 74 and on the camera housing for preventing the admission of light between the members and the camera housing.

In the operation of a camera including liquid-spreading device 70, members 72 and 74 are spaced apart in inoperative position by manually depressing buttons 102. A film unit comprising a photosensitive and second sheet secured together in superposed relation is introduced between members 72 and 74 into passage 50 and moved therethrough, with the two sheets being separated and advanced into exposure position. Members 72 and 74 are then moved together into operative position with the leading end section of the film unit extending through the spreading gap between end walls 80 and 88, spacing members92 acting to properly locate the film unit with respect to device 70 during insertion of the film unit within the camera. Following exposure of the photosensitive sheet of the film unit, the leading end portion of the film unit is manually grasped for withdrawing the film unit through the spreader gap for superposing the photosensitive and second sheets of the film unit and spreading a processing liquid in -a layer therebetween. At the end of a predetermined processing period, the second sheet, preferably carrying a positive photographic print, may be stripped from the photosensitive sheet.

Since certain changes may be .made in the above apparatus without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. Photographic apparatus for exposing and thereafter treating a photographic film unit including a photosensitive sheet, a second sheet superposable with said photosensitive sheet and means containing a processing liquid, said apparatus comprising, in combination, a camera for exposing the photosensitive sheet of a film unit and including a passage through which said film unit may be withdrawn from said camera following exposure therewithin and means associated with said camera for spreading said liquid in a uniform layer of predetermined thickness between said photosensitive and second sheets during withdrawal of said film unit from said camera, the last-mentioned means including a pair of substantially straight rigid members, means for securing said members parallel to one another and spaced a predetermined distance apart to provide a gap through which said film unit is moved, said gap between said members comprising a throat for generating pressure in said liquid between the sheets of said film unit to distribute said liquid in a layer between said sheets during movement thereof through said throat between said members, means for so mounting said members on said camera adjacent said passage that said film unit can be manually withdrawn in a plane from said camera through said passage and said gap, the lastmentioned means mounting said members for pivotal movement with respect to one another and said camera about a single axis located substantially in the plane of withdrawal of said film unit from said camera through said passage, said members being pivotable apart to permit the movement of a film unit therebetween without causing pressure to be created in the liquid carried by said film unit, and said members, when secured together to form said pressure-generating throat, being so pivotable with respect to said camera in response to movement of said film unit as to automatically assume and maintain a proper and substantially constant position relative to the plane of movement of said film unit.

2. The apparatus of claim 1 wherein said means for pivotally mounting said members form a substantially lighttight chamber exterior of said camera within which said film unit may be withdrawn through said passage from said camera and through said throat in the absence of actinic light.

3. A photographic device for distributing a liquid in a layer between two layers of photographic sheet material, said device being adapted to use in combination with photographic apparatus from which said sheet material is manually withdrawn and comprising, in combination, a pair of substantially rigid members secured together in juxtaposed relation and having substantially straight parallel adjacent portions predeterminedly spaced apart to form a pressure-generating gap through which said sheet material is movable in a plane, said members being so constructed as to eifect the distribution of said liquid in a layer between layers of said sheet material during movement of said material through said gap, and means 1O mounting said rigid members on said apparatus for pivotal movement with respect to said apparatus about an axis in the plane of movement of saidsheet material through said gap and substantially parallel to said portions of said I rigid members defining said gap in response to movement of said sheet material from said apparatus through said gap so as to'maintain a substantially constant position relative to said plane of movement of said sheet material.

4. A photographic device for distributing a liquid in a uniform layer of predetermined thickness between two layers of photographic sheet material, said device being adapted to use in combination with photographic apparatus from which said sheet material is manually withdrawn and comprising, in combination, a pair of substantially parall l rigid members secured in juxtaposition and predeterminedly spaced apart to permit the movement of said sheet material in a plane therebetween, the gap between said members comprising a throat for generating pressure in a liquid between said layers of sheet material to distribute said liquid in a layer therebetween during movement of said sheet material in said plane through .said throat between said members, and means mounting vsaid rnembers on said apparatus for pivotal movement with respect tosaid apparatus about an axis which is in said plane of movement of said sheet material through said throat and substantially parallel with the portions of said members comprising said throat, the last-named :HlfiflIlSSO mounting said members that said sheet material can be withdrawn in said plane from said apparatus through said gap between said members and said members automatically adjust their position relative to said apparatus in response to movement of said sheet material through said gap so as to maintain a substantially constant position relative to said plane of movement of said sheet material.

5. The combination, in a photographic film unit including a photosensitive sheet adapted to be exposed in a camera, a second sheet superposable with said photosensitive sheet and means containing a processing liquid, of a device for distributing said processing liquid between said sheets in a uniform layer of predetermined thickness during withdrawal of said sheets from said camera, said device being adapted to use in combination with said camera and comprising a pair of substantially rigid members secured together in juxtaposed relation and having substantially parallel straight sections predeterminedly spaced apart to form a throat through which said sheets are movable in a plane for generating pressure in said liquid between said sheets to distribute said liquid in a layer therebetween during movement of said sheets through said throat, and means for so mounting said members on said camera that said sheets can be manually withdrawn from said camera in a plane through said throat 'between said members, said means mounting said members for pivotal movement with respect to said camera about an axis located in the plane of movement of said sheets from said camera through said throat and substantially parallel with said straight sections of said rigid members, said members defining said pressure-generating throat being so pivotable about said axis as to automatically adjust their position relative to said camera in response to movement of said sheets so as to assume a substantially constant position relative to said plane of movement of said sheets.

6. Photographic apparatus for exposing and thereafter processing photosensitive sheet material by a liquid distributed in a layer between said exposed photosensitive sheet material and another sheet material superposed therewith, said apparatus comprising, in combination, a camera for exposing said photosensitive sheet material, a pair of substantially parallel rigid members secured in juxtaposition and predeterminedly spaced apart to permit the movement of said sheet material therebetween substantially in a plane, the gap between said members comprising a throat for generating pressure in a liquid between layers of said sheet material to distribute said liquid in a layer therebetweenduring movement of said sheet material in said plane through said throat between said members, and means mounting said members on said camera for pivotal movement with respect to said camera about an axis which is substantially in said plane of movement of said sheet material and substantially parallel with the portions of said rigid members defining said throat, the last-named means so mounting said members that said sheet material can be manually withdrawn in said plane from said camera through said gap between said members and said members are capable of automatically adjusting their positionrelative to said camera in response to movement of said sheet material through said gap so as to maintain a subsantially constant position relative to said plane of movement of said sheet material.

7. Photographic apparatus for exposing and thereafter treating a photographic film unit including a photosensitive sheet, a second sheet superposable with said photosensitive sheet and means containing a processing liquid, said apparatus comprising, in combination, a camera for exposing the photosensitive sheet of a film unit, said camera including a passage through which said film unit may be withdrawn from said camera following exposure therewithin, and means associated with said camera 'for spreading said liquid in a uniform layer of predetermined thickness between said photosensitive and second sheets during withdrawal of said film unit from said camera, the

last-mentioned means including a pair of substantially parallel rigid members secured in juxtaposition and predeterminedly spaced apart to permit the movement of said film unit therebetween substantially in a plane, the gap between said members comprising a throat for generating pressure in said liquid between the sheets of said film unit to distribute said liquid in a layer between said sheets during movement thereof through said throat between said members in said plane, and means for so mounting said members on said camera adjacent said passage that said film unit can be manually withdrawn in said plane from said apparatus through said gap between said members, the lastmentioned means mounting said members for pivotal movement with respect to said apparatus about an axis located substantially in said plane of withdrawal of said film unit from said camera and substantially parallel with the portions of said rigid members comprising said gap, said members defining said pressure-generating throat being so pivotable as to automatically adjust their position relative to said camera in response to movement of said film unit so as to maintain a substantially constant position relative to said plane of movement of said sheets.

ReferencesCited in the file of this patent UNITED STATES PATENTS 2,483,389 wolfi- Oct. 4, 1949 

